Chemiluminescence reaction chamber

ABSTRACT

Gaseous sample mixture and gaseous reactant mixture are brought together at one edge of a shallow disc-shaped reaction chamber. The exhaust opening of the reaction chamber is located diametrically from the mixture inlet. A light transmitting element forms one wall of the reaction chamber and the reacting gases pass through the reaction chamber in a plane substantially parallel to the light transmitting element.

United States Patent [191 Warnick et a1. Mar. 5, 1974 [54] CHEMILUMINESCENCE REACTION 3,451,780 6/1969 Prescott at al. 23 254 E CHAMBER 3,520,660 7/1970 Webb 23/253 3,615,241 10/1971 Low .1; 23/253 Inventors: Alan Warnick, Oak Park; Cassimer 3,647,387 3/1972 Benson et al. 23/254 M. Kukla, Taylor, both of Mich. 3,679,312 7/1972 Mansbcrg 23/230 B [73] Assignee: Ford Motor Company, Dearborn,

Mich. Primary ExaminerMorris O. Wolk Assistant ExaminerR. E. Serwin [22] Flled: Sept 1971 Attorney, Agent, or Firm-Glenn S. Arendsen; Robert A. Benziger; Keith L. Zerschling [21] Appl. No.: 180,823

[52] US. Cl. 23/254 R, 23/232 R, 356/246 ABSTRACT [51] Int.l Cl.f G0ln 27/68. Gaseous Sample mixture gaseous reactant mixture ['58] Fwd 0 Search g ggag ggb are brought together at one edge of a shallow disc- 3 shaped reaction chamber. The exhaust opening of the 56 R f d reaction chamber is located diametrically from the l 1 e erences mixture inlet. A light transmitting element forms one UNITED STATES PATENTS wall of the reaction chamber and the reacting gases 3,245,758 4/1966 Bcnzingcr et a1. 23/230 pass through the reaction chamber in a plane substan- 1 1/1966 Narita et a1 2 5 tially parallel to the light transmitting element. 3,287,089 11/1966 Wilbum 23/254 3,399,974 9/1968 Spencer et a1. 23/254 E 8 Claims, 4 Drawing Figures t 2 9 J2 2d; 3 I I ///////k;

I CHEMILUMINESCENCE REACTION CHAMBER BACKGROUND OF THE INVENTION This invention relates to the subject matter of US. patent application Colvin et al. Ser. No. 146,927, now US. Pat. No. 3,746,514, entitled Chemiluminescent Instrument", and Warnick et a1. Ser. No. 146,929, now US. Pat. No. 3,746,513, entitled chemiluminescent Process" both filed May 26, 1971.

vPrior to the inventions described in the above applications, chemiluminescence reactions involving gaseous constituents of gaseous mixtures were carried out in relatively large, well stirred reaction chambers at extremely low pressures of 1 Torr or less. One factor that lead to the inventions of the above applications was the difficulty of reproducing the degree of mixing of the sample mixture and the reactant mixture. The inventions described in the applications solved this difficulty by providing substantially laminar flow of the sample mixture and the reactant mixture into the reaction chamber at a location proximate to the inner surface of a light transmitting element and drawing the reaction products perpendicularly away from the light transmitting element. Accuracy, sensitivity and reproducibility were improved greatly by maintaining a substantially stable portion of the chemiluminescent reaction as close as possible to a light sensing device located just outside'of the light transmitting element. I

SUMMARY OF THE INVENTION This invention provides a chemiluminescence reaction chamber that has increased accuracy, sensitivity and reproducibility over a wide range of reaction chamber pressures. The reaction chamber comprises a housing that defines a reaction space having a depth less than its width. A light transmitting element is mounted in the housing along the width of the reaction space so that the light transmitting element forms one side of the reaction space. A sample passage extends throughthe housing and opens into the reaction space so that the axis of the sample passage opening lies in a plane substantially parallel to and just inside of the plane of the light transmitting element. A reactant passage also extends through the housing and opens into the reaction space with its axis lying in substantially the same plane as the axis of the sample passage opening. The reactant passage opening also is closely adjacent to the sample passage opening. An exhaust opening for the reaction space is located across the reaction space from the sample passage opening and the reactant passage opening.

Sample mixture and reactant mixture enter and pass through the reaction space with substantially laminar flow in a plane substantially parallel to the light transmitting element. A highly stable portion of the chemilu minescence reaction occurs as the mixtures pass across the light transmitting element toward the exhaust opening.

Reaction space depth preferably is just slightly greater than the streams of sample mixture and reactant mixture passing through the reaction space. Reaction spaces having more or less depth tend to promote turbulence and a resulting decrease in stability and reproducibility. The sample mixture opening and the reactant mixture opening preferably are located at the midpoint of the depth. Cylindrical, oval, rectangular or other shapes of reaction spaces can be used.

The exhaust opening can extend through the housing in substantially the same plane as the sample passage and reactant passage openings. In an alternate construction, the housing contains a relatively deep chamber and a baffle extends through the chamber in a plane substantially parallel to the light transmitting element to define the inner surface of the reaction space. The baffle has an opening located remotely from the sample passage opening and the reactant passage opening and that baffle opening serves as the exhaust opening for the reaction space.

The sample passage opening and the reactant passage opening can be merged into a common opening located in a wall of the reaction space. Accuracy and sensitivity are optimized by forrnng the sample passage and the reactant passage so the axes thereof intersect at approximately a right angle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a partially sectioned plan view of a reaction chamber of this invention having a baffle extending through the housing to define the inner surface of the reaction space.

FIG. 2 is a sectional view taken along lines 22 of FIG. I to show more clearly the baffle and its exhaust opening. V

FIG. 3 is a sectioned plan view of an alternate construction in which the exhaust opening extends through the wall of the housing in substantially the same plane as the sample passage and reactant passage openings.

FIG. 4 is a sectioned view of a chamber similar to that of FIG. 3 except that the sample passage opening is located concentrically within the reactant passage openmg.

DETAILED DESCRIPTION Referring primarily to FIGS. 11 and 2, the reaction chamber housing comprises a cup-shaped rear portion 10 and a cylindrically-shaped front portion 12. A light transmitting element 14 is mounted sealingly in one surface of front portion 12 and cooperates with rear portion I0 and front portion 12 to define a closed cylindrical chamber 316.

A baffle plate 118 extends through chamber 16 in a plane substantially parallel to and spaced a short distance into the chamber from light transmitting element 114. The edges of baffle plate T8 are sandwiched between rear portion It) and front portion 12. An 0 ring 2t) seals the junction of the front and rear portions radially outward of the baffle plate. Baffle plate 18 is continuous except for a small segment-shaped opening 24 located at one side of the aligned inner walls of rear portion II) and front portion 12.

A sample passage 26 extends through thewall of front portion 112 and opens into chamber 116 on the side opposite from opening 24. The axis of sample passage 26 forms substantially a 45 angle with an imaginary line 27 that perpendicularly bisects the inner edge 25 of .opening 24. A reactant passage 28 also extends through the wall of the front portion 12 in the same plane as sample passage 26 but at a angle thereto. Reactant passage 28 joins with sample passage 26 just short of the inner surface of chamber 16 so that the merged passages have a common opening 30. Opening 30 is located in the vertical plane of imaginary line 27 (FIG. 1). A passage 32 is formed in rear portion to communicate with the portion of chamber 16 located behind baffle plate 18.

The reaction chamber is installed in a chemiluminescent instrument by connecting the sample mixture to sample passage 26 and the reactant mixture to reactant passage 28. An exhaust pump is connected to passage 32 to draw the sample mixture and reactant mixture into reaction space 19. The sample mixture and the reactant mixture blend together and flow out of opening 30 laterally through the reactant space 19. Chemiluminescence occurring while the sample mixture and the reactant mixture are flowing through the reactant space is transmitted through light transmitting element 14 to a light measuring device (not shown) located outside of element 14. The gases eventually pass through opening 24 and are drawnout of exhaust pas-- sage 32.

The reaction chamber of FIG. 3 comprises a one piece housing 34 defining a shallow cylindricallyshaped reaction space 36. Sample conduit 26a and reactant-conduit 28a extend through the housing and open into reaction space 36 in.a manner similar to that illustrated in FIG. 1 except that the passages are formed in the side of housing34 rather than a corner. An exhaust passage 32a extends through the wall of housing 34 diametrically across reaction space 36 from the common opening 30a of the sample passage and the reactant passage.

In FIG. 4, a sample passage 26b extends through the wall of housing 3412 on the axis of exhaust opening 32b. Sample passage 26b is mounted concentrically within a reactant passage 28b. The sample mixture and the reactant mixture blend smoothly as the mixtures flow through reaction space 36b toward exhaust opening Optimized width and depth of the reaction space depend on several factors. Reaction space width generally must be sufficient to contain at least a major amount of the reaction. Good stability and sensitivity over a pressure ranging from about 5 to over 500 Torr are provided for the chemiluminescence reaction of nitric oxide and ozone by a reaction space having a diameter (width) of 1 inch and a depth of three-eighths inch. Depth variations of i Vs inch from this value have minimal effect on performance and it appears that larger variations can be tolerated.

The size of the openings of the sample passage and reactant passage also influence stability and sensitivity. A common opening 30 having a depth of one-eighth inch produces satisfactory results in the chemiluminescence reaction space. The essentially elliptical shape of common opening 30 is desirable because the chemiluminescence reaction is occurring in a fairly wide stream upon entering the reaction space. Openings of numerous other shapes can be used as desired, with the preferred openings having a larger width than depth.-

Thus this invention provides a reaction chamber for a chemiluminescence reaction that is inexpensive and produces good stability and sensitivity over a wide range of pressures. The reaction chamber maintains virtually all of the chemiluminescence reaction occurring within the reaction space in a plane adjacent the light transmitting element.

We claim:

1. A reaction chamber for a chemiluminescence reaction between a gaseous sample mixture and a gaseous reactant mixture comprising a housing having a constant volume reaction space therein, said reaction space having a depth less than its width,

a light transmitting element mounted in said housing along the width of said reaction space, said light transmitting element forming one side of said reaction space and defining a first plane,

a sample passage extending through said housing and opening into said reaction space, said sample passage opening being in a plane substantially perpendicular to said first plane and arranged to direct a sample flow substantially parallel to said first plane,

a reactant passage extending through said housing and opening into said reaction space, said reactant passage opening being in a plane substantially perpendicular to said first plane and arranged to direct a reactant flow substantially parallel to said first plane,

said sample passage opening positioned with respect to said reactant passage opening so that the sample and reactant are brought together at one edge of the reaction space,

an exhaust opening for said reaction space, said exhaust opening being located across the reaction space from the sample passage opening and the reactant passage opening.

2. The reaction chamber of claim 1 in which the sample passage opening and the reactant passage opening are merged into a common opening.

3. The reaction chamber of claim 2 in which the axis of the sample passage forms approximately a right angle with the axis of the reactant passage.

4. The reaction chamber of claim 3 in which the common opening of the sample passage and the reactant passage has a width greater than its depth.

5. The reaction chamber of claim 4 comprising a baffle extending through said housing in a plane substantially parallel to the light transmitting element, said baffle defining the inner surface of said reaction space, said baffle having an opening located remotely from the common opening of the sample passage and the reactant passage, said opening serving as the exhaust opening for the reaction space.

6. The reaction chamber of claim 4 in which the axis of the exhaust opening is located in substantially the same plane as the axis of the common opening of the sample passage and the reactant passage.

7. The reaction chamber of claim 1 in which the axis of the exhaust opening is located in substantially the same plane as the axes of the sample passage opening and the reactant passage opening.

8. The reaction chamber of claim 1 wherein the rear wall of the reaction space comprises a baffle extending through said housing in a plane substantially parallel to the light transmitting element, said baffle having an opening located remotely from the common opening of the sample passage and the reactant passage, said opening serving as the exhaust opening for the reaction 

2. The reaction chamber of claim 1 in which the sample passage opening and the reactant passage opening are merged into a common opening.
 3. The reaction chamber of claim 2 in which the axis of the sample passage forms approximately a right angle with the axis of the reactant passage.
 4. The reaction chamber of claim 3 in which the common opening of the sample passage and the reactant passage has a width greater than its depth.
 5. The reaction chamber of claim 4 comprising a baffle extending through said housing in a plane substantially parallel to the light transmitting element, said baffle defining the inner surface of said reaction space, said baffle having an opening located remotely from the common opening of the sample passage and the reactant passage, said opening serving as the exhaust opening for the reaction space.
 6. The reaction chamber of claim 4 in which the axis of the exhaust opening is located in substantially the same plane as the axis of the common opening of the sample passage and the reactant passage.
 7. The reaction chamber of claim 1 in which the axis of the exhaust opening is located in substantially the same plane as the axes of the sample passage opening and the reactant passage opening.
 8. The reaction chamber of claim 1 wherein the rear wall of the reaction space comprises a baffle extending through said housing in a plane substantially parallel to the light transmitting element, said baffle having an opening located remotely from the common opening of the sample passage and the reactant passage, said opening serving as the exhaust opening for the reaction space. 